1,215 research outputs found

    Potassium-doped BaFe2As2 superconducting thin films with a transition temperature of 40 K

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    We report the growth of potassium-doped BaFe2As2 thin films, where the major charge carriers are holes, on Al2O3 (0001) and LaAlO3 (001) substrates by using an ex-situ pulsed laser deposition technique. The measured Tc's are 40 and 39 K for the films grown on Al2O3 and LaAlO3, respectively and diamagnetism indicates that the films have good bulk superconducting properties below 36 and 30 K, respectively. The X-ray diffraction patterns for both films indicated a preferred c-axis orientation, regardless of the substrate structures of LaAlO3 and Al2O3. The upper critical field at zero temperature was estimated to be about 155 T.Comment: 6 pages including 3 figure

    Regional characteristics of fine aerosol mass increase elucidated from long-term observations and KORUS-AQ campaign at a Northeast Asian background site

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    Funding Information: This research was supported by the National Research Foundation of Korea (NRF), funded by the Ministry of Science and ICT (MSIT) (NRF2020M3G1A111499813). S. Lim was supported by the National Research Foundation of Korea (NRF) from the Ministry of Science and ICT (2018R1D1A1B07050849 and 2021R1C1C2011543). M. Lee thanks to the support by the National Research Foundation of Korea (NRF) funded by the Ministry of Science and ICT (NRF2020R1A2C301459213). S.-W. Kim was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF), funded by the Ministry of Education (2017R1D1A1B06032548). Funding to K.-S. Kang was provided by the National Institute of Environmental Research (NIER-RP2017-166). Funding Information: This research was supported by the National Research Foundation of Korea (NRF), funded by the Ministry of Science and ICT (MSIT) (NRF2020M3G1A111499813). S. Lim was supported by the National Research Foundation of Korea (NRF) from the Ministry of Science and ICT (2018R1D1A1B07050849 and 2021R1C1C2011543). M. Lee thanks to the support by the National Research Foundation of Korea (NRF) funded by the Ministry of Science and ICT (NRF2020R1A2C301459213). S.-W. Kim was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF), funded by the Ministry of Education (2017R1D1A1B06032548). Funding to K.-S. Kang was provided by the National Institute of Environmental Research (NIER-RP2017-166). Publisher Copyright: Ā© 2022 The Author(s)Northeast Asia has suffered from severe PM2.5 pollution and the exact mechanisms have yet to be fully understood. Here, we investigated the transformation processes of submicron aerosols using a 4-year data set obtained at Jeju, a Northeast Asian background site. The diurnal-cycle constrained empirical orthogonal function analysis of nanoparticle size-number distribution distinguished 2 modes: burst of nucleation-Aitken particles and increase in accumulation mode particles, representing ā€œnew particle formation and growthā€ and ā€œPM2.5 mass increase,ā€ respectively. In these events, aerosol and meteorological characteristics changed progressively over several days, revealing that the PM2.5 mass increase is an episodic event occurring on a regional scale. The increase in PM2.5 mass was accompanied by an increase in aerosol liquid water content, which correlated well with SO4-2 and NO3, and a decrease in incoming solar radiation (-14.1 Wm-2 day-1) constituting a positive feedback. The ā€œtransport/hazeā€ episode of KOREA-U.S. Air Quality campaign corresponds to ā€œPM2.5 mass increase,ā€ during which the vertical evolution of particles demonstrates that nanoparticles ā‰„3.5 nm were entrained into the shallow boundary layer upon vertical mixing and converted to accumulation-mode particles ā‰„0.3 mm at relative humidity (RH) exceeding the deliquescence RH of secondary inorganic aerosol (SIA). Coincidently, at ground, the coating thickness of refractory black carbon (rBC) (48 Ā± 39 nm) and SIA concentration increased. Furthermore, the diameter of rBC (180-220 nm)-containing particle in core-shell configuration linearly increased with PM2.5 mass, reaching 300-400 nm at PM2.5 ā‰„ 40 mg m-3.This observational evidence suggests that the thick coating of rBCs resulted from the active conversion of condensable gases into the particulate phase on the rBC surface, thereby increasing the mass of the accumulation-mode aerosol. Consequently, this result complies with the strategy to reduce primary emissions of gaseous precursors for SIA and particulates such as rBC as a way to effectively mitigate haze pollution as well as climate change in Northeast Asia.Peer reviewe

    In-situ fabrication of cobalt-doped SrFe2As2 thin films by using pulsed laser deposition with excimer laser

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    The remarkably high superconducting transition temperature and upper critical field of iron(Fe)-based layered superconductors, despite ferromagnetic material base, open the prospect for superconducting electronics. However, success in superconducting electronics has been limited because of difficulties in fabricating high-quality thin films. We report the growth of high-quality c-axis-oriented cobalt(Co)-doped SrFe2As2 thin films with bulk superconductivity by using an in-situ pulsed laser deposition technique with a 248-nm-wavelength KrF excimer laser and an arsenic(As)-rich phase target. The temperature and field dependences of the magnetization showing strong diamagnetism and transport critical current density with superior Jc-H performance are reported. These results provide necessary information for practical applications of Fe-based superconductors.Comment: 8 pages, 3figures. to be published at Appl. Phys. Let

    Structural studies on Helicobacter pylori ATP-dependent protease, FtsH

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    The crystal structures of the Helicobacter pylori FtsH ATPase domain in the nucleotide-free state and complexed with ADP have been determined

    Short range scattering effect of InAs quantum dots in the transport properties of two dimensional electron gas

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    Short range interaction between two dimensional electron gas (2DEG) and InAs quantum dots embedded in the GaAs/AlGaAs quantum well is investigated as a function of carrier density. At low carrier density the interaction is significantly characterized by a transport to quantum lifetime ratio of less than 5. However, with an increase in carrier density, quantum lifetime is observed to undergo a sharp transition from 0.17 to 0.25 ps. This is attributed to the screening of short range repulsive scattering due to InAs quantum dots by the 2DEG.open7

    Antiosteoporosis Activity of New Oriental Medicine Preparation (Kyungokgo Mixed with Water Extract of Hovenia dulcis

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    Protective effect of new oriental medicine (Kyungokgo mixed with water extract of Hovenia dulcis, KOGHD) was assessed on the bone loss induced mice by ovariectomy. In the in vivo experiments, antiosteoporosis effect of KOGHD was investigated using ovariectomized osteoporosis mice model. After 6 weeks of treatment, the mice were euthanized, and the effect of Kyungokgo (KOG) and KOGHD on body weight, spleen weigh, thymus weight, uterine weight, serum biochemical indicators, bone weight and length, immune cell population, bone morphometric parameters, and histological stains was observed. Our results showed that KOGHD prevented the deterioration of trabecular microarchitecture caused by ovariectomy, which were accompanied by the lower levels of bone turnover markers and immune cell population as evidenced by the inhibition of RANKL-mediated osteoclast differentiation without cytotoxic effect on bone marrow derived macrophages (BMMs). Therefore, these results suggest that the Hovenia dulcis (HD) supplementation in the KOG may also prevent and treat bone loss

    Staged Surgery for Chronic Primary Aortoduodenal Fistula in a Septic Patient

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    Aortoenteric fistula is one of the most challenging problems that confront the vascular surgeons. Controversy remains over the optimal treatment because of the continued publication of series with high mortality, amputation, and aortic disruption rates. A positive preoperative blood culture is the best predictor of mortality with increased amputation rates due to infection of the extra-anatomic bypass. Therefore, in selected cases with sepsis, a prudent management protocol is required. We report a 68-yr-old male presenting with a chronic primary aortoduodenal fistula extensively involving the duodenum and Gram-negative sepsis. We planned a staged operation. Initially, an emergency laparotomy and control of the aorta allowed stabilization of the patient, identification of the fistula, and direct in situ placement of the prosthetic graft followed by an en bloc resection of the aneurysm and the surrounding structures. After he recovered from sepsis and had been stabilized, a staged extra-anatomic bypass followed by transabdominal removal of the temporarily placed graft was done. This management plan will allow the highest success rate and may be a prudent management protocol for these difficult cases

    Torsion of the Gallbladder: Report of a Case

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    Torsion of the gallbladder is a rare entity that is difficult to diagnose preoperatively. The condition occurs most often in the elderly. Although its etiology is unknown, a constant finding is the presence of the gallbladder on a mobile mesentery (floating gallbladder). Torsion, or volvulus, of the gallbladder occurs when it twists axially, with the subsequent occlusion of bile and/or blood flow. Herein, a case of torsion of the gallbladder is presented where preoperative computed tomographic scan and laparoscopy were successfully used to diagnose and treat this condition without the usual requirement of open exploration. Given the possibility of laparoscopic cholecystectomy and the increasing incidence with which torsion of the gallbladder is being witnessed today, the importance of a preoperative computed tomographic scan is emphasized when there is a high index of clinical suspicion

    Interdigitating dendritic cell sarcoma occured alone in axilla

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    Interdigitating dendritic cell sarcoma (IDCS) is a very rare disease around the world and its prognosis is known to be aggressive. This reports a case diagnosed as IDCS of the axillary region treated in Soonchunhyang University Hospital. A 57-year-old female visited Soonchunhyang University Hospital with a left axillary mass. The mass was hard and fixed. Computed tomography observed a 7 cm lymph node at the left axilla, and core biopsy suspected sarcoma. In another study, there was no specific finding except the axillary lesion. Left axillary lymph node dissection (level I, II) was conducted and the pathologic report finally showed IDCS. The patient was treated with only radiotherapy and followed up without recurrence for 13 months up to now. IDCS is a very rare sarcoma that is hard to diagnose and progresses fast. Thus, treatment is very difficult. Proper treatment can be better established after more experiences

    PIAS1 regulates CP2c localization and active promoter complex formation in erythroid cell-specific Ī±-globin expression

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    Data presented here extends our previous observations on Ī±-globin transcriptional regulation by the CP2 and PIAS1 proteins. Using RNAi knockdown, we have now shown that CP2b, CP2c and PIAS1 are each necessary for synergistic activation of endogenous Ī±-globin gene expression in differentiating MEL cells. In this system, truncated PIAS1 mutants lacking the ring finger domain recruited CP2c to the nucleus, as did wild-type PIAS1, demonstrating that this is a sumoylation-independent process. In vitro, recombinant CP2c, CP2b and PIAS1 bound DNA as a stable CBP (CP2c/CP2b/PIAS1) complex. Following PIAS1 knockdown in MEL cells, however, the association of endogenous CP2c and CP2b with the Ī±-globin promoter simultaneously decreased. By mapping the CP2b- and CP2c-binding domains on PIAS1, and the PIAS1-binding domains on CP2b and CP2c, we found that two regions of PIAS1 that interact with CP2c/CP2b are required for its co-activator function. We propose that CP2c, CP2b, and PIAS1 form a hexametric complex with two units each of CP2c, CP2b, and PIAS1, in which PIAS1 serves as a clamp between two CP2 proteins, while CP2c binds directly to the target DNA and CP2b mediates strong transactivation
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